Quite, and it has the enormous advantage that I can extract all data using nothing more than an XML parser, rather than having a two stage [parse XML -> parse embedded DSL] parser for special cases. Even the media aspects of the srcset could probably be better expressed (with more verbosity though) as a standard XML structure.

I really wish it was - though I'm far from a fan of XML for most cases, it does work rather well for this when used as intended...